▎ 摘　　要

NOVELTY - Treatment of substrate involves combining substrate and graphene oxide with each other in liquid (L1) to form an intermediate compound, removing at least portion of liquid (L1) from intermediate compound, and thermally treating the intermediate compound so that the graphene oxide is at least partially fixed to the substrate, to obtain treated material comprising treated hollow fiber membranes. The substrate comprises hollow fiber membranes, each having a side wall, comprising a base material and an inner lumen, which is delimited by the side wall. The side wall has an outer surface provided with pores having diameter of 0.1-15 mu m and an inner surface provided with pores having diameter of 5-200 nm. The base material comprises at least one chosen from polysulfone, polyethersulfone, and/or its derivatives. USE - Treatment of substrate e.g. porous substrate such as non-treated polysulfone hollow fibers used for contacting with fluid such as liquid (claimed) such as water and aqueous solution for removal of organic molecule such as caffeine, ofloxacin, rhodamine B, diclofenac, benzophenone-3, benzophenone-4, carbamazepine, bisphenol A, from fluid. ADVANTAGE - The method enables simple and quick treatment of substrate having excellent capacity for absorption of mixture of organic pollutants, and without requiring coextrusion of the different components and/or dissolving of one component and re-precipitation in the presence of the other. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) treated material, which comprises treated hollow fiber membrane in which at least 20%, preferably 40% or more outer surface of treated hollow fiber membrane is coated with graphene oxide; and (2) usage of treated material, which involves placing treated material in contact with said fluid which is a liquid.